Cartons having their upper end sealed and in the form of oppositely disposed, aligned gables are widely used as containers for such liquids as milk and juices. Such cartons are well accepted as they are dimensioned for convenient storage and once opened can be repeatedly closed and opened and are easily disposed of when emptied.
Such cartons are formed from blanks provided with established fold lines which (in the case of a gable to be converted into a pouring spout) establish side walls having upper portions which are inclined toward each other and end walls having upper portions consisting of central and marginal triangular sections. The central sections are inclined towards each other and the marginal sections are inclined upwardly with their margins sealed together and to the upper portions of the side walls which also have fold lines defining triangular sections similar to the sections sealed thereto. The fold lines of the blanks are in the form of small channels.
The conversion of a gable into a pouring spout includes the steps of first forcing the two marginal sections of the end wall apart to break the seal between them. With the two marginal sections positioned to establish an angle of at least 180.degree., the marginal triangular sections are pushed forwardly and upwardly to rupture the seal between them and the similar upper portions of the side walls.
Usually, the cartons are easily opened following this procedure but frequently the procedure is unsuccessful making it necessary to sever the seals, as with a knife.